diff --git a/include/openmc/distribution_multi.h b/include/openmc/distribution_multi.h
index 1b1a262b82..ae7768ac31 100644
--- a/include/openmc/distribution_multi.h
+++ b/include/openmc/distribution_multi.h
@@ -45,8 +45,8 @@ public:
   Direction sample(uint64_t* seed) const;
 
   // Observing pointers
-  auto mu() const { return mu_.get(); }
-  auto phi() const { return phi_.get(); }
+  Distribution* mu() const { return mu_.get(); }
+  Distribution* phi() const { return phi_.get(); }
 
 private:
   UPtrDist mu_;  //!< Distribution of polar angle